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mafic

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Journal Article
Journal: Geology
Published: 01 June 1977
Geology (1977) 5 (6): 377–383.
...R. G. Tysdal; J. E. Case; G. R. Winkler; S.H.B. Clark Abstract A Paleocene to Eocene(?) mafic sequence of igneous rocks on Knight Island and a Cretaceous mafic and ultramafic sequence of the Resurrection Peninsula in coastal southern Alaska are characterized by pillow basalts, sheeted dikes...
Journal Article
Published: 01 March 1977
Canadian Journal of Earth Sciences (1977) 14 (3): 444–455.
... metasedimentary rocks. Field relationships, petrography, and chemical characteristics of the Boundary intrusions indicate that they are composed of three compositionally distinct, sequentially emplaced groups. From oldest to youngest, these are (1) a mafic augite- and biotite-bearing mela-dioritic group, (2...
Journal Article
Journal: Geology
Published: 01 February 1977
Geology (1977) 5 (2): 105–110.
...Michael R. Perfit Abstract Rocks dredged from 16 localities withing the Cayman Trench suggest a crustal sequence identical to that reported from the mid-oceanic ridge. Serpentinites, serpentinized peridotites, cumulate mafic rocks, and gabbros crop out deep along the precipitous north-trending...
Journal Article
Journal: Geology
Published: 01 February 1977
Geology (1977) 5 (2): 68.
Journal Article
Published: 01 February 1977
Journal of the Geological Society (1977) 133 (2): 123–131.
... show that they are derived from at least two sets of parent rocks. TABLE I : Comparison of rock-types in mafic-ultramafic associations of Scourian and Laxfordian complexes In Scourlan complex Components of layered maflc-ultramaflc bodies U1tramaflc: olivlne-rock, metaperidotite, meta- pyroxenite...
Journal Article
Journal: GSA Bulletin
Published: 01 January 1977
GSA Bulletin (1977) 88 (1): 96–100.
... and initial Sr 87 /Sr 86 intercepts of the monzonite and gneiss are 1,680 m.y. and 0.7020 for the quartz monzonite and 1,880 m.y. and 0.7015 for the country rock. At least three distinct generations of mafic dikes are present in the Sierra Madre; field relations with dated units indicate ages of ∼2700 m.y...
Journal Article
Journal: GSA Bulletin
Published: 01 December 1976
GSA Bulletin (1976) 87 (12): 1753–1762.
Journal Article
Published: 01 November 1976
Canadian Journal of Earth Sciences (1976) 13 (11): 1591–1601.
...Harold Williams; R. D. Dallmeyer; R. K. Wanless Abstract Zircons from the Twillingate Granite form a linear array with a concordia intercept of 510 + 17 – 16 m.y. Mafic dikes that cut deformed granite along the southern contact of the pluton at New World Island record 40 Ar/ 39 Ar hornblende ages...
Journal Article
Published: 01 November 1976
Canadian Journal of Earth Sciences (1976) 13 (11): 1577–1583.
...Peter Petö; Richard Lee Armstrong Abstract Twenty-seven whole-rock samples of granitic rocks and associated mafic inclusions define a Rb–Sr ispchron of 156 ± 6 m.y. with an initial ratio of 0.70415 ± 0.00017 (95% confidence limits). K–Ar and Rb–Sr data for granodiorite, quartz monzonite...
Journal Article
Journal: Economic Geology
Published: 01 November 1976
Economic Geology (1976) 71 (7): 1131–1158.
...A. J. Naldrett; L. J. Cabri Abstract Ultramafic and related mafic rocks can conveniently be classified in terms of the tectonic environment in which they were emplaced. Among those bodies emplaced in an orogenic environment one can distinguish synvolcanic bodies, both intrusive and extrusive...
Journal Article
Published: 01 August 1976
American Mineralogist (1976) 61 (7-8): 638–642.
Journal Article
Published: 01 July 1976
Canadian Journal of Earth Sciences (1976) 13 (7): 1003–1005.
...Roy V. Beavon Abstract A thin formation of folded mafic flows resting unconformably on Archean basement is informally named the Spi Lake basalt. Stratigraphic, structural, and textural evidence suggests that these lavas were probably fed from a diabase dike swarm dated at 2250+ m.y...
Journal Article
Published: 01 July 1976
Canadian Journal of Earth Sciences (1976) 13 (7): 898–907.
...L. D. Schutts; A. Brecher; P. M. Hurley; C. W. Montgomery; H. W. Krueger Abstract It appears that a hydrothermal alteration and development of magnetite is largely responsible for a paleomagnetic resetting in a belt of mafic–intermediate rocks in eastern Massachusetts. The age of this thermal...
Journal Article
Journal: Geology
Published: 01 July 1976
Geology (1976) 4 (7): 443–446.
Journal Article
Journal: AAPG Bulletin
Published: 01 June 1976
AAPG Bulletin (1976) 60 (6): 952–961.
...J. T. Dutro, JR.; P. Brosge William; M. A. Lanphere; H. N. Reiser Abstract Rocks in the Doonerak anticline resemble correlative sequences in the northeastern Brooks Range more than they resemble the directly adjacent sequence in the north-central Brooks Range. Mafic dikes in the anticline have...
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Journal Article
Journal: GSA Bulletin
Published: 01 June 1976
GSA Bulletin (1976) 87 (6): 909–914.
... and mineral separates mark another intrusive event at 2,200 ± 35 m.y. B.P., well after the regional metamorphism. Two episodes of mafic dike emplacement are consistent with field relations but are not in agreement with recent K-Ar age determinations. Geological Society of America 1976 geochronology...
Journal Article
Published: 01 May 1976
Geological Magazine (1976) 113 (3): 193–232.
Journal Article
Journal: Geology
Published: 01 April 1976
Geology (1976) 4 (4): 201–205.
... shield areas abound in xenoliths of ultramafic-mafic volcanic rocks, minor silicic volcanic rocks, and derived and (or) chemical sedimentary rocks. No confident oldest age limits were set on these xenoliths, which antedate the development of the true greenstone belts in these areas and are thought...
Journal Article
Published: 01 March 1976
Canadian Journal of Earth Sciences (1976) 13 (3): 476–489.
Journal Article
Published: 01 January 1976
Geological Magazine (1976) 113 (1): 61–76.